The circularly-polarized antenna is used extensively in global positioning system (GPS), satellite, and radar applications. In the ground station of a particular application, a circularly-polarized antenna requires a good axial ratio (AR) everywhere above the horizon from the zenith (directly overhead) to very low elevation angles near the horizon. As is known in the art, the axial ratio is the ratio of vertical electric field (Evert) component and the horizontal electric field (Ehor) component of the radiation. Some traditional designs, such as microstrip patches or helix antennas, are not usable as circularly-polarized antennas due to their poor AR at low elevation angles.
To improve the axial ratio of polarization antennas at low elevation angles (e.g., at elevations within 25 degrees of the horizon), a three-dimensional (3D) spatial structure is required. Some prior art circularly-polarized antennas include four dipoles arranged at a 45 degree orientation angle relative to the horizontal plane and in which each opposing pair of dipoles is mutually perpendicular. It is difficult to maintain this precise perpendicular orientation between opposite pair of dipoles. Significant mechanical engineering (ME) is required to design the assembling fixture, special ME supports, special ME assembling methods and, perform the analysis to ensure long term quality.
For the reasons stated above and for other reasons stated below which will become apparent to those skilled in the art upon reading and understanding the specification, there is a need in the art for improved systems and method.